1. Technical Field
Embodiments generally relate to electronic circuits and, more specifically, to near-field radio frequency communication devices. Such devices are generally known as NFC (Near Field Communication) devices.
2. Discussion of the Related Art
More and more radio frequency communication devices are capable of operating in near field with a fixed terminal or another mobile device. In particular, most mobile phone type telecommunication devices are now equipped with a near-field communication (NFC) router.
It is generally spoken of NFC devices operating in card mode (or emulating a card), as opposed to a second operating mode of these devices, which is to emulate a card reader to cooperate with another near-field device. The device then behaves as a terminal.
There are different near-field communication standards. The difference between such standards essentially is the modulation and coding type of data to be transmitted. Formerly, transponders were most often dedicated to one type of modulation. They are now designed to be able to operate according to different modulation types and can thus be configured to set this type for each new transaction with a terminal.
The modulation type is most often set by the terminal, and the transponder-type device modifies the configuration of its NFC router to be able to communicate with the reader.
Usually, the router or the radio frequency front head capable of operating according to different modulations successively switches to these different modulations until it recognizes a request transmitted by a reader. This however takes time.
Further, some terminals are themselves capable of operating according to different modulation types to be able to adapt to transponders dedicated to a single type. In this case, the terminal successively sends requests according to the different types until it receives a response in one of the types. However, the terminal should leave enough time between two types (generally on the order of a few milliseconds) so that a configurable transponder also has time to scan the different modulation types until both configurations (terminal and transponder) match.
Such a configuration process is long and makes the device in card mode risk never to detect a request.